Abstract

Normal diode lasers with average output powers of 1 W or more exhibit bad beam quality and therefore cannot be applied for high-precision applications or nonlinear optics. Therefore an external output coupling mirror was used in our experiments. Diffraction-limited operation was achieved, which yielded 400 mW of power and a factor-of-12 improvement in brightness. With this resonator type 1.1 W of average output power was also obtained, with a beam propagation factor of 2.6 in the slow axis; fast axis emission is always diffraction limited.

Figures (5)

Beam caustic along the slow axis behind a 75-mm lens when the external resonator was optimized for beam quality. For an output power of 400 mW at a wavelength of 940 nm a propagation factor M2=1.03±0.06 was obtained.

Beam caustic along the slow axis behind a 75-mm lens when the external resonator was optimized for optical power. For an output of 1.1 W at a wavelength of 940 nm a propagation factor M2=2.57±0.08 was obtained.